#!/bin/sh

# Requires: xfconf-query (xfce4-settings), polybar

# Swaps xfce4-panel out of the XFCE session for polybar, and can put the

# panel back.

#

# xfce4-panel is not an autostart .desktop entry — xfce4-session launches it

# as one of its own session clients, so it has to be replaced there. This is

# a script rather than a checked-in xfconf XML file for the same reason as

# rofi-keybinds.sh: xfconf rewrites its config atomically, by rename, which

# would replace a symlink from this repo with a regular file.

#

# Usage: polybar-panel.sh            apply (idempotent, safe to re-run)

#        polybar-panel.sh --remove   put xfce4-panel back

#        polybar-panel.sh --list     show which session clients run what

#

# Applying also swaps the running session live; no logout needed.

set -u

CHANNEL=xfce4-session

BACKUP="${XDG_DATA_HOME:-$HOME/.local/share}/polybar-panel.backup"

# xfwm4's compositor shadows a dock as a rectangle the size of its window,

# ignoring what the window actually paints. polybar's bar spans the screen and

# is transparent everywhere except the islands, so that shadow shows up as a

# band hanging across the empty middle. Turning it off is the only knob for it;

# true is xfwm4's default, which --remove puts back.

dock_shadow() {

    command -v xfconf-query >/dev/null 2>&1 || return 0

    xfconf-query -c xfwm4 -p /general/show_dock_shadow -s "$1" 2>/dev/null ||

        xfconf-query -c xfwm4 -p /general/show_dock_shadow -n -t bool -s "$1"

}

# Where the polybar launcher lives. The repo layout is the default; point

# POLYBAR_LAUNCH somewhere else to use an installed copy instead.

LAUNCH=${POLYBAR_LAUNCH:-$(CDPATH= cd -- "$(dirname -- "$0")/../polybar" 2>/dev/null && pwd)/launch.sh}

[ -f "$LAUNCH" ] || LAUNCH="$HOME/.config/polybar/launch.sh"

[ -x "$LAUNCH" ] || { echo "polybar-panel: no executable launcher at $LAUNCH" >&2; exit 1; }

command -v xfconf-query >/dev/null 2>&1 ||

    { echo "polybar-panel: xfconf-query not found — is this an XFCE session?" >&2; exit 1; }

command -v polybar >/dev/null 2>&1 ||

    { echo "polybar-panel: polybar is not installed" >&2; exit 1; }

# Every session client command in every stored session, as "prop<TAB>[cmd,args]".

clients() {

    xfconf-query -c "$CHANNEL" -lv |

        sed -n 's|^\(/sessions/[^/]*/Client[0-9]*_Command\) *\(\[.*\]\)$|\1\t\2|p'

}

# Set an array property from a "[a,b,c]" literal.

set_array() {

    prop=$1

    args=""

    IFS=,

    for word in $(printf '%s' "$2" | sed 's/^\[//; s/\]$//'); do

        args="$args -t string -s $word"

    done

    unset IFS

    # shellcheck disable=SC2086

    xfconf-query -c "$CHANNEL" -p "$prop" $args --force-array

}

case "${1:-}" in

--list)

    clients | while IFS='	' read -r prop cmd; do

        printf '%-45s %s\n' "$prop" "$cmd"

    done

    ;;

--remove)

    [ -f "$BACKUP" ] || { echo "polybar-panel: nothing to restore ($BACKUP not found)" >&2; exit 1; }

    while IFS='	' read -r prop cmd; do

        [ -n "${prop:-}" ] || continue

        set_array "$prop" "$cmd"

        echo "restored $prop -> $cmd"

    done <"$BACKUP"

    rm -f "$BACKUP"

    dock_shadow true

    polybar-msg cmd quit >/dev/null 2>&1 || pkill -u "$(id -u)" -x polybar

    [ -n "${DISPLAY:-}" ] && command -v xfce4-panel >/dev/null 2>&1 &&

        (xfce4-panel >/dev/null 2>&1 &)

    ;;

"")

    found=0

    clients | while IFS='	' read -r prop cmd; do

        case "$cmd" in

        "[xfce4-panel"*)

            printf '%s\t%s\n' "$prop" "$cmd" >>"$BACKUP"

            set_array "$prop" "[$LAUNCH]"

            echo "$prop -> $LAUNCH"

            ;;

        esac

    done

    clients | grep -q "$LAUNCH" && found=1

    [ "$found" = 1 ] || { echo "polybar-panel: no xfce4-panel session client found" >&2; exit 1; }

    dock_shadow false

    if [ -n "${DISPLAY:-}" ]; then

        pgrep -u "$(id -u)" -x xfce4-panel >/dev/null 2>&1 &&

            xfce4-panel --quit >/dev/null 2>&1

        "$LAUNCH" >/dev/null 2>&1 &

        echo "polybar started; xfce4-panel stopped"

    fi

    ;;

*)

    echo "usage: polybar-panel.sh [--remove|--list]" >&2

    exit 1

    ;;

esac